In this article:
- What is osteoporosis?
- Risk factors for osteoporosis
- How the thyroid affects bone health
- Reducing your risk for osteoporosis
The thyroid affects every cell in your body, including the cells in your bones. Not surprisingly, fluctuations in your thyroid hormones can have significant consequences on your bone structure and strength. By regulating your thyroid hormones, you can prevent bone disease and its complications.
What is osteoporosis?
The term osteoporosis means "porous bones." In this condition, your bones become fragile and are prone to breakage.
It may seem surprising, but our bones are living, moving tissues that are continually breaking down and building back up—a process called bone remodeling and repair. Our bones do this to repair any damages and to facilitate growth.
Two types of cells control bone remodeling and repair: osteoclasts and osteoblasts. Osteoclasts break down bone, whereas osteoblasts build bone back up. Osteoporosis occurs when your body breaks down more bone than it can repair. Thus, you lose bone density and strength, which increases your risk for fractures.
Risk factors for osteoporosis
According to the National Osteoporosis Foundation, osteoporosis affects about 54 million Americans. Everyone is at risk for osteoporosis. However, it is more common in people over age 50. Women are also at disproportionately high risk for osteoporosis, as 1 in 2 women will experience a bone fracture due to osteoporosis compared to 1 in 4 men. Additionally, a family history of osteoporosis or bone fracture increases your risk exponentially.
Aside from age, sex, and family history, several other factors can increase your risk for osteoporosis, including:
- Autoimmune disorders (Rheumatoid arthritis, lupus, multiple sclerosis)
- Gastrointestinal disorders (Celiac disease, inflammatory bowel disease)
- Cancer (specifically of the prostate and breast)
- Nervous system disorders (stroke, Parkinson's, spinal cord injuries)
- Endocrine disorders (hypothyroidism, hyperthyroidism, diabetes, thyrotoxicosis, abnormal menstrual periods, premature menopause)
- Mental illness (eating disorders, diabetes)
- Lung disease
- Weight loss surgery (gastric bypass, gastric sleeve, etc.)
- Unhealthy diet
- Poor exercise
Certain medications can also increase your risk for osteoporosis, including steroids and common anti-reflux drugs.
How thyroid function affects bone health
Thyroid hormone helps control the rate at which we replace our bones.
Hyperthyroidism is the condition in which the thyroid gland makes too much thyroid hormone.
Hyperthyroidism has a pronounced effect on bone mass due to high bone turnover. A meta-analysis of 25 studies shows that bone mineral density decreases in patients with hyperthyroidism who are untreated. Bone breaks down more quickly, and so osteoblasts cannot keep up. You end up having more bone breakdown than re-building.
Treatment of hyperthyroidism may have a positive effect on bone metabolism. Still, there isn't enough research yet to draw firm conclusions.
Hypothyroidism is the state in which the thyroid gland does not produce enough thyroid hormones.
Hypothyroidism may impair bone turnover. It can reduce bone resorption (the process by which osteoclasts break down the tissue in bones and release the calcium into the blood) and osteoblastic activity, which builds up new bone. These changes in bone metabolism may increase bone mineral density. However, there is currently no definitive data on the relationship between bone mineral density and hypothyroidism in adults.
People with hypothyroidism need to take thyroid hormone replacement medication to achieve normal thyroid hormone levels. Taking too much thyroid medication can put you in a hyperthyroid state, a risk factor for osteoporosis.
Importance of vitamin D for bone health
Vitamin D is a fat-soluble vitamin naturally present in a few foods, added to others, and available as a dietary supplement. You can also get vitamin D from sun exposure.
Vitamin D promotes calcium absorption in the gut and maintains adequate calcium and phosphate levels in the blood to enable normal bone mineralization and to prevent muscle cramps and spasms. It is also necessary for bone growth and bone remodeling by osteoblasts and osteoclasts.
Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Together with calcium, vitamin D also helps protect older adults from osteoporosis.
Relationship between vitamin D and thyroid health
Research suggests that people with Hashimoto's and hypothyroidism may have low levels of vitamin D and calcium.
There are a few possible explanations for why people with hypothyroidism have low vitamin D levels. Firstly, people with hypothyroidism may not be able to absorb vitamin D from foods and supplements adequately. Secondly, people with hypothyroidism may not effectively activate vitamin D. Finally, some side effects of hypothyroidism may cause low vitamin D. For example, people with hypothyroidism may spend less time outside in the sun because they have fatigue or low energy.
While there appears to be a positive correlation between vitamin D deficiency and hypothyroidism, it's unclear whether low vitamin D levels cause thyroid dysfunction or a side effect of thyroid disease.
So, while hypothyroidism is not a direct risk factor for osteoporosis, you might conclude that you may be at greater risk of developing weak bones if you have low vitamin D levels with hypothyroidism. You can screen for vitamin D status with a.
Caution with calcium
Calcium is essential for bone health. However, calcium supplements and foods high in calcium (like dairy products) can interfere with thyroid medication absorption. Therefore, you may not get your full dose of thyroid medication. If you take a calcium supplement, you should take it at least 4 hours before or after taking your thyroid medication. A good rule of thumb is to take your thyroid medication either when you wake up or go to bed and take your calcium supplement at the opposite time of day.
Reducing your risk for osteoporosis
Osteoporosis is a 'silent disease' because you cannot feel your bones weakening. Indeed, many people don't know they have osteoporosis until they break a bone, start to lose noticeable height, or have spinal curvature.
Beyond fractures, osteoporosis can be debilitating, especially to older adults who may struggle with limited mobility. Additionally, bone fractures can lead to severe complications, such as pneumonia.
To reduce your likelihood of having osteoporosis, you need first to identify any risk factors. Women in particular need to take early preventative measures to ward off osteoporosis, which can occur rapidly after menopause. (The average age of menopause is 51.) This is especially pertinent for women who reach menopause at an earlier age.
If you have a thyroid condition like hyperthyroidism or hypothyroidism, work with your thyroid doctor to optimize thyroid health and medication. Aside from managing other health conditions that may lead to osteoporosis, the International Osteoporosis Foundation recommends the following preventative measures:
- Have regular bone density scans.
- Get an early diagnosis.
- Eat a diet rich in calcium, vitamin D, and protein, essential for bone health. Most doctors recommend people (especially women) supplement calcium and vitamin D to ensure they are getting adequate daily amounts.
- Have a healthy body weight, as being too thin or too heavy can increase your risk.
- Stay active with regular strengthening and weight-bearing exercises.
- Avoid heavy smoking and alcohol consumption.
- Spend time in the sun to synthesize vitamin D in your skin. (Make sure to take preventative measures to avoid skin cancer).